SOLUTION: Find the exact solution 8^(x-1)=16^(x+3) I keep getting 3 log(2^x-1)=4 log(2^x+3) which I turn into a big string of : 3 log (2) + x log (2) - log (2) = 4 log (2) + x log (2) +

Algebra ->  Logarithm Solvers, Trainers and Word Problems -> SOLUTION: Find the exact solution 8^(x-1)=16^(x+3) I keep getting 3 log(2^x-1)=4 log(2^x+3) which I turn into a big string of : 3 log (2) + x log (2) - log (2) = 4 log (2) + x log (2) +      Log On


   



Question 799369: Find the exact solution 8^(x-1)=16^(x+3)
I keep getting 3 log(2^x-1)=4 log(2^x+3)
which I turn into a big string of :
3 log (2) + x log (2) - log (2) = 4 log (2) + x log (2) + 3 log (2)
Which I simplify to :
x log (2)= 5 log (2) + x log (2)
but that doesnt seem right, wont the x log (2)'s cancel out?

Found 2 solutions by stanbon, solver91311:
Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
Find the exact solution 8^(x-1)=16^(x+3)
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Change both sides to base "2":::
(2^3)^(x-1) = (2^4)^(x+3)
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= 2^(3x-3) = 2^(4x+12)
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= 3x-3 = 4x+12
x = -15
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Cheers,
Stan H.
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Answer by solver91311(24713) About Me  (Show Source):
You can put this solution on YOUR website!


You started off on the right foot, but you will have a much easier time of it if you take the base 2 log of both sides.









But since



from which it follows:



John

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